On the optimization of soft-magnetic properties of metallic glasses by dynamic current annealing

The Structure and Magnetic Properties of Rapidly Quenched Fe72Ni8Nb4Si2B14 Alloy

“…As has been shown in Figure 6 relaxation process is still not complete. The cut-off frequency for Ta dependence indicates how the annealing process affects the µ" peak position that may be correlated with the reorganization of the magnetic domains during glass relaxation [30]. The downward trend in the cut-off frequency suggest that slow reorganization of the local structure occurs during aging process and some α-Fe clusters may form and grow.…”

“…From the point of view of the crystal structure, aging in metastable quenched metallic glasses induces a lower enthalpy, a smaller volume, a more stable glassy state and changes the topological short-range order, which is characteristic for the glass structure [23][24][25][26][27][28] Some of the previous studies have shown that the relaxation process of FeNiSiB systems can be divided into two stages: the first-metalloid atoms movement, the second-diffusion of the constituent atoms [29]. From the magnetic point of view, the elimination of internal stresses can improve the mobility of the Bloch wall of the magnetic domain [30] and, as a consequence, the magnetic anisotropy fluctuates during the change of the topological short-range order caused by the aging/rejuvenation process [31]. As the relative permeability is inversely proportional to the anisotropy constant, the magnetic saturation increases with the local structure change and the decrease in anisotropy constant [32].…”

Thermal effect on structural and magnetic properties of Fe78B13Si9annealed amorphous ribbons

“…Escobar et al [3] have reported, also like Kronmüller quoted by Luborsky [7], the coercive field dependence on temperature [8]. H. Kronmüller, in [9], again pointed out that the defect concentration and fluctuations affect the magnetic properties of amorphous alloys.…”

“…Knowledge of the crystallization kinetics of amorphous alloys offers the possibility for specific crystalline structures and hence for optimizing their properties. The elimination of both internal and external stresses improves the mobility of the Bloch walls of magnetic domains and facilitates reorientation of spins and magnetic saturation under an applied field H. Stress relaxation is observed by annealing the amorphous alloy at temperatures allowing sufficient atomic diffusion for structural relaxation but not enough to initiate crystallization [3]. The optimization of softmagnetic properties of metallic glasses can be made by dynamical current annealing, One can obtain the structure relaxation, where the atoms rearrange to become more ordered with increasing annealing temperature, without bulk crystallization occurring.…”

“…This behavior may be compared with the results of Escobar et a1. [3] who optimized the magnetic properties of Fe-Si-B alloys by a very short annealing at 430°C. But it seems that the absolute magnetic saturation of this alloy occurs at higher field in accordance with the work of Pankhurst et a1 [10], who using Mossbauer studies did not reach the saturation state for the same composition with applied field of up to 5T.…”